Good luck, I've tried multiple brands of brake quieter, even got for to turn all four rotors and replace the pads. They were quiet for a few months and now they squeal like a stuck pig again. No burnouts and no track time, just daily commuting. If it really bothers you it's time for aftermarket rotors and pads.

To respond to above mine squeal at low speed stops even after warmup and at any temp/weather situation. This is my fifth mustang and I never had an issue with my other GTs.

 

My aftermarket pads and rotors squeak too

 

Hmmm, well I guess in the end I didn't buy a mustang because it is quiet. Still love the car, and I can use it as an excuse for some brembos.